1. Field of the Invention
The present invention relates generally to assay/detection devices for detecting the presence of analyte in a field sample and, more specifically to an assay/detection device and method for detecting certain human metabolic by-products in toilet or urinal effluent.
2. Description of Related Art
Immunochromatographic assays, also called lateral flow tests or simply strip tests, are well known in the relevant arts. They are a logical extension of the technology used in latex agglutination tests, which have been available since the 1950's. The benefits of immunochromatographic tests include the fact that they are available in a user-friendly format, that only a short time is needed to obtain a result, that they exhibit long-term stability over a wide range of climates and that they are relatively inexpensive to manufacture.
These features make strip tests ideal for applications such as home testing, rapid point of care testing, and testing in the field for various environmental and agricultural analytes. In addition, they provide reliable testing that might not otherwise be available to third world countries.
The principle utilized in these tests is straightforward. Basically, any ligand that can be bound to a visually detectable solid support, such as dyed microspheres, can be tested for qualitatively, and in many cases even semi-quantitatively.
Immunochromatographic assays of the above type typically utilize a membrane as a solid support in a dipstick or flow-through device. These devices are available for drugs of abuse (cocaine, cannabinoid, amphetamines, opiates, PCP), pregnancy and fertility and infectious disease (chlamydia, Strep A, infectious mononucleosis, etc.). Some of the more common lateral flow tests currently on the market are tests for pregnancy, Strep throat, and Chlamydia. These are examples of conditions for which a quantitative assay is not necessary. The usual packaging for such assays is a membrane, typically cellulose, enclosed in a plastic holder. The device is then typically further packaged singly or in bulk in a sealed foil or plastic pouch which acts as an environmental control.
The plastic holder keeps the membrane in a suitable configuration in order to ensure correct functioning of the entire device. The usual test procedure involves opening the outer packaging and removal of the plastic device, followed by application of a sample through a sample window by dipping the device into the sample or by dropping the sample onto the sample window. After waiting the recommended amount of time, the results can be checked by checking the sample window for a positive or negative result. The result is typically indicated by a change in color of the test strip.
In the case of human metabolic by-products, the foregoing procedure assumes that a sample of urine is available for testing. In some cases, it may be advantageous to collect a sample or carry out a diagnostic test of urine without the knowledge of the subject being tested. Uses for this system would provide a screening or monitoring system for parents, counselors, coaches or other interested individuals.
There exists a need, therefore, for a diagnostic detection device and method which is inexpensive to manufacture, which provides at least a qualitative indication of the presence of a specific analyte and which can be administered in a relatively unobtrusive fashion.
There exists a need for such a diagnostic detection device which can be mounted quickly and easily within a commode or urinal, which device will provide an indication of the presence of a specific analyte upon flushing the commode or urinal.
There exists a need for such a device and method which can be used to test for the presence of the metabolic by-products of controlled substances including tetrahydrocannabinol, cocaine, opiates, barbiturates, amphetamine and methamphetamine.